Cisplatin combination drugs induce autophagy in HeLa cells and interact with HSA via electrostatic binding affinity

Abstract

Cisplatin, as a significant chemotherapeutic drug for the treatment of cancers, was combined with rapamycin (RAPA), an autophagy inducer, or 3-methyladenine (3-MA), an autophagy inhibitor, and these cisplatin combination drugs were tested with HeLa cells to explore their specific effects on autophagy by cell viability assay, mitochondria membrane potential (MMP) determination, transmission electron microscopic (TEM) observation, dansylcadaverine (MDC) staining, and western blotting analysis. Results revealed that cisplatin combination drugs enhanced formation of autophagosomes, and morphological and biochemical markers of autophagy in HeLa cells can be clearly determined with the formation of enlarged acidic vesicles and conversion of light chain 3 (LC3) protein. Cisplatin combination drugs induce stronger effects on autophagy than either of the components does. Combination drug-induced autophagy inhibits the growth of HeLa cell in a dose-dependent manner and subsequently sensitizes the cells to apoptosis and cell death. Furthermore, interactions between cisplatin combination drugs and human serum albumin (HSA) were investigated under fluorescence, synchronous fluorescence, and circular dichroism analysis. Results suggest that cisplatin combination drugs can bind to HSA and induce conformation and microenvironmental changes of HSA via electrostatic binding affinity. These investigations can provide useful and fundamental information, which could be used in cytotoxic chemotherapy to dramatically increase efficacy in pharmaceutical and biotechnology fields.